Speed shift for a phonograph player drive

ABSTRACT

The invention provides a drive with speed shift suitable for driving a phonograph turntable for playing records at different speeds, selectively, such as 33 rpm records at one setting of the drive and 45 rpm records at another one setting of the drive. It comprises a belt drive utilizing an elastic belt of polygonal (square) cross section forming the connection between a drive shaft pulley carrying two or more adjacent V-grooves and a driven cylindrical drum. The pulley with the V-grooves is mounted on a shaft which is disposed parallel to the axis of the drum. The Vgrooves are of the same angle of groove, but of different diameters and each cooperates through the belt with the drum to provide two or more selectable turntable speeds by means of a fork shifter for shifting of the belt from one V-groove to another, or the other V-groove, while the belt aligns itself in a plane normal to the axis of the drum. The belt is square in cross section. It racks on two of its adjacent sides in the V-grooves but on one side only of the drum. The driving pulley has two adjacent V-grooves with a ridge between them, which ridge has two spaced apart diagonal grooves inclined in opposite directions for assisting the shifting of the belt from one groove to the other and vice versa for selecting the drive ratio appropriate for the speed of the record on the turntable. The drive ratio is changeable by raising or lowering an axially movable speed selecting rod shift which extends axially a short distance above the center of the turntable. This makes possible a player simple in construction, convenient and reliable in operation and excellent in performance. The complete player mechanism including the turntable with its connected motor drive belt transmission and speed shift, comprises a unitary operative assembly suitable to be mounted on a supporting base board, without elaborate housing.

United States Patent [191 Estkowski 1 SPEED SHIFT FOR A PHONOGRAPHPLAYER DRIVE [75] Inventor: Michael H. Estkowski, St. Joseph,

Mich.

[73] Assignee: V-M Corporation, Benton Harbor,

Mich.

[22] Filed: May 24, 1973 21 Appl. No.: 363,579

[52] US. Cl 274/9 A [51] Int. Cl. Gllb 3/00 [58] Field of Search 274/39R, 39 A, 9 A, l E;

[56] References Cited UNITED STATES PATENTS 1,471,726 10/1926 Ginty74/242.4 2,051,819 8/1936 Carson 274/9 A Primary ExaminerHarry N.Haroian Assistant Examiner-John W. Shepperd Attorney, Agent, orFirm-Johnson, Dienner, Emrich, Verbeck & Wagner [57] ABSTRACT Theinvention provides a drive with speed shift suit- [4 Oct. 1,1974

able for driving a phonograph turntable for playing records at differentspeeds, selectively, such as 33 rpm records at one setting of the driveand 45 rpm records at another one setting of the drive. It comprises abelt drive utilizing an elastic belt of polygonal (square) cross sectionforming the connection between a drive shaft pulley carrying two or moreadjacent V-grooves and a driven cylindrical drum. The pulley with the V-grooves is mounted on a shaft which is disposed parallel to the axis ofthe drum. The V-grooves are of the same angle of groove, but ofdifferent diameters and each cooperates through the belt with the drumto provide two or more selectable turntable speeds by means of a forkshifter for shifting of the belt from one V-groove to another, or theother V-groove, while the belt aligns itself in a plane normal to theaxis of the drum. The belt is square in cross section. It racks on twoof its adjacent sides in the V-grooves but on one side only of the drum.The driving pulley has two adjacent V-grooves with a ridge between them,which ridge has two spaced apart diagonal grooves inclined in oppositedirections for assisting the shifting of the belt from one groove to theother and vice versa for selecting the drive ratio appropriate for thespeed of the record on the turntable. The drive ratio is change able byraising or lowering an axially movable speed selecting rod shift whichextends axially a short distance above the center of the turntable. Thismakes possible a player simple in construction, convenient and reliablein operation and excellent in performance. The complete player mechanismincluding the turntable with its connected motor drive belt transmissionand speed shift, comprises a unitary operative as sembly suitable to bemounted on a supporting base board, without elaborate housing.

1 Claim, 4 Drawing Figures k l I: gZiZT'IIILI: Z; 3 16 SPEED SHIFT FOR API-IONOGRAPH PLAYER DRIVE BACKGROUND OF THE INVENTION to satisfy thedemand for a player suitable for youthful PRIOR ART The prior art ofrecord players has failed to furnish a simple, rugged, low-costconstruction such as the present invention makes possible.

OBJECTS OF THE INVENTION The primary object of the invention is toprovide a rugged, high quality performance record player of simple andreliable construction at a cost low enough to allow the player of thisinvention to be put into the hands of children.

An incidental object is to provide a novel drive with greatly simplifiedand easily understood and operated speed selector for phonographs andthe like.

The preferred form of the drive involves two rotatable members withtheir axes parallel. One is a drive shaft; the other is a driven drum.The drive shaft mounts a pulley having two V-grooves of differentdiameters side-by-side on the same axis, and a driven cylindrical drummember presenting the same diameter to each of the V-grooves of thepulleys and being on an axis parallel to the axis of said pulleys. Theprofile of each groove is substantially rectangular for maximumeffective area of engagement between the two adjacent sides of the beltand the V-grooves of the pulley.

A single belt, of rectangular cross section, sufficiently elastic tooperate on the drum and the larger diameter V-pulley, and of sufficienttension and friction grip to provide a satisfactory drive is trainedover the drum and either of the V-grooves of the pulley. The driveratios taking into account the appropriate synchronous speed of thedriving electric motor provide rotation of the drum and turntable at 33rpm when the drive is through the smaller diameter pulley, and 45 rpm ofthe drum and turntable when the drive is through the pulley of largerdiameter.

A desirable feature of the present invention allows the shifter fork, orequivalent, to be moved from one speed position to another speedposition with a full stroke spring throw while the drive is inoperation, and the drive belt will find its corresponding positionaccording to the setting of the shifter fork. This is preferably aidedby one or more diagonal cuts or transfer grooves in the ridge betweengrooves on the pulley whereby the belt will move into the selected driveratio for playing the corresponding record at, for example, 33 rpm or 45rpm, according to the setting of the shifter fork. An indication of thespeed at which the selector is set may be registered on the shiftermember, which member preferably extends up through the central axis ofthe drum and the attached plate.

The pulley is provided with a diagonal shift groove on one side of thepulley for assisting transfer from 33 to 45 rpm and with an appropriatediagonal shift groove preferably on the opposite side of the pulley forassisting in transfer from 45 to 33 rpm drive.

Thus the annular ridge dividing the two grooves may bear a diagonal cutto assist the belt to be transferred from the low speed to the highspeed groove and a similar diagonal cut in the opposite direction may bedis posed in the dividing ridge between the two grooves for shifting thebelt in the opposite direction.

The significance of the joint operation of the full stroke mechanismproduced by the over center spring 29 connected to the shifter fork andthe diagonal shifting grooves 26-26 lies in the fact that they, incombination with the moving belt, constitute a power driven shift of thedrive ratio. The full stroke snap action spring 29 throws the fork 9which carries the run of the belt embraced by the fork laterally all theway endwise of the pulley to its new final driving position, and themoving pulley brings the diagonal transfer groove 26 with its leadingend into registration with the part of the belt which has been moved tothe shifted position-that is, in registration with the receiving groove16 or ]l3-with the result that the belt is thrown into the transfergroove and thence into the desired full circle groove 16 or 17. Thus,with minimum effort, the run of the belt from one groove to the other isaccomplished with rapidity and certainty, and minimum wear on the belt.

DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view of the turntableas though viewed from the top of FIG. 2 with the margins of theturntable broken away;

FIG. 2 is a vertical longitudinal section taken on the line 22 of FIG. 1showing the drive in high speed position;

FIG. 3 is a view similar to FIG. 2 except that the speed selector andconnected parts has been shifted to the low speed drive; and

FIG. 4 is a side elevational view of the pulley with two V-grooves forthe corresponding speeds of drive and showing also one of the spiralgrooves to assist the driving belt in climbing out of one groove overinto the other when the shifter fork is set accordingly.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 2 and 3 show thesupporting base 1 which may be part of a cabinet or container. A throughopening 2 permits parts of the mechanism to extend below the support 1.Over the opening 2 there is disposed a frame plate 3 upon which themoving parts, hereinafter described, are mounted. The frame plate 3supports two main items--namely, the motor with its connected parts 4and the hollow axle 5 which is set into and staked, or otherwisesecured, to the frame plate 3. This hollow axle 5 provides a centralbore through which extends the manual shifter rod 6. The rod 6, whichmay bear indications of its position, is slidable in the said sleeve 5and carries at its lower end the hub 7 of bracket member 8. This bracketmember 8 carries on its outer end a shifter fork 9 which containsashifter slot 10 with upper and lower fingers 11 and 12 between which isdisposed, at all times, the belt 13. The belt 13 is preferably anelastic endless band (of square cross section) which embraces the pulley14 carried on the motor drive shaft 15 and fixed thereto. The pulley l4has two V-grooves l6 and 17. The groove 16 at the upper end of the motorshaft is of a diameter such that when the belt 13 is in the groove 16and trained around the drum 18, the drum l8 and the connected turntable19 will rotate at 33 rpm for a given synchronous speed of the motor 4.When the belt 13 is shifted to the groove 16 of the upper part of thedrive, the belt 13 remains on the same diameter of the drum 18, which isa plain cylinder, and the drive turntable 19 will be at 45 rpm.

The turntable 19 has at its outer periphery a cylindrical wall 20extending above and below the central horizontal disc 21 which disccarries on its lower face a cylindrical flouge which forms the largediameter pulley 18 with which the belt 13 cooperates. The central partof the disc 21 has a hub portion 22 in which there is mounted a bearingsleeve 23 to form an antifriction journal with the post 5, which post 5is fixed at its lower end in the frame plate 3.

The upper end of the post 5 carries a groove in which a hairpin spring24 is engaged and the function of which is to cooperate with the washer25 to avoid accidental raising of the turntable 19 relative to the post5.

The depending rim of the cylindrical wall 20 encloses the drive parts,as will be apparent from FIGS. 2 and 3.

The shifting of the belt 13 axially of the drum 18 is accomplished bypulling up on the pin 6 from its position shown in FIG. 3 to raise it tothe position shown in FIG. 2 whereby the forks 11 and 12 may pull up onthe belt 13 when the same is in the position shown in FIG. 2; or bydownward motion of the operating pin 6, depress the belt in the uppergroove 16 as shown in FIG. 2 to cause the same to cross over theintervening annular ridge between the two grooves as by way of adiagonal groove 26 cut in the ridge 27 dividing the two grooves 16 and17. The annular position of the operating pin 6 and its attached bracket8 is maintained by a projection 28 formed integral with the body of thebracket or arm 8 and extending up through a slot in the frame plate 3.This arm 28 bears a finger at its upper end to limit downward travel ofthe bracket 8 and connected parts. An over center biasing spring 29 willhold the bracket 8 yieldingly in either extreme up or extreme downposition to facilitate the shifting of the belt from one V-groove to theother V-groove, and to hold it there,

It is to be observed that a groove similar to the groove 26 shown inFIG. 4, on the side of the pulley 14 facing the reader, there is aduplicate groove on the opposite side which is in register with thegroove 26 and which, being on the side opposite the groove 26, willshift the belt in the direction opposite to that which the groove 26 ofFIG. 4 will shift the belt.

In the operation of the device, as a substitute for the bracket arm 8mounted on the lower end of the operating pin 6 and moved by bodilyshifting the same, a first class lever may be substituted to providemeans for shifting the belt 13. The shifting pin 6 is preferablyprovided with indicia (not shown) indicating the position of the partsin respect of the rotational speed for which the mechanism is set. Theupper surface of the turntable 19 has a central annular flange 33 of asize to enter and fill the hole at the center of a record adapted forrotational speed of 45 rpm.

In operation, the electric motor is energized to drive the turntable atthe appropriate speed for the record to be played. The central annularflange 33 is of a diameter to enter the central hole of the 45 rpmrecords. The position of the 45 rpm records, in an up and downdirection, is maintained by the raised ring or flange 35, the belt beingat that time disposed in the groove of larger diameter.

For records adapted to be operated at 33 rpm, the central hole isthreaded over the operating pin 6 to center the same and the outer rimof the record rests upon the flange 36.

The specific speeds and sizes may, of course, be anything which theplaying of a specific record demands. Preferably, suitable indicia willbe applied to the operating pin 6 to indicate the speed for which themechanism is set.

The operation of the device is apparent from the foregoing descriptionof the structure. The motor is energized; the appropriate record ismounted on the turntable; and the tone arm with pick up of usual or anydesirable construction is then applied to the groove of the record onthe turntable. Suitable mechanism for stopping the rotation when therecord has been played, of any suitable character, may be utilized.

The present invention is specifically related to the construction andoperation of the speed control of the turntable drive and is notconcerned directly with the pick up equipment.

I claim:

1. In combination, a supporting base plate (3) adapted to be disposedhorizontally, a stationary bearing sleeve (5) mounted on and extendingvertically above the base plate (3) and opening through and below thebase plate, a turntable (19) having an upper record supporting face (21)and a downwardly extending central hub (22, 23) said turntable embracingand being rotatably mounted on said bearing sleeve (5), a cylindricaldriving drum (18) mounted on the lower side of the turntable (19), avertical motor drive shaft (15) rotatably mounted on said base plate (3)within the lateral confines of the outer edge of the turntable and thedrum (18), a pulley (14) on said shaft (15) in horizontal register withthe drum (18), said pulley (14) having two contiguous parallel V-grooves(l6, 17) of different diameters, an elastic belt (13) of substantiallysquare cross section adapted to embrace the drivingdrum with a flat sideof the belt and one or the other of said V-grooves with two contiguoussides of the belt, a normally stationary shifter fork (9) embracing thebelt (13) and being mounted on the base for transverse movement relativeto the belt to shift the belt from one V-groove to the other, a overcenter snap action spring connected between the fork and the base plategoverning the stationary positions and movements of the fork, and aplunger rod (6) slidably disposed in said bearing sleeve (5) and havingits upper end disposed above the plane of the record supporting face(21) of the tumtable whereby said rod (6) can be raised or depressed bythe fingers of the operator, said plunger rod (6) being connected at itslower end to the fork (9) to provide said transverse movement.

1. In combination, a supporting base plate (3) adapted to be disposedhorizontally, a stationary bearing sleeve (5) mounted on and extendingvertically above the base plate (3) and opening through and below thebase plate, a turntable (19) having an upper record supporting face (21)and a downwardly extending central hub (22, 23) said turntable embracingand being rotatably mounted on said bearing sleeve (5), a cylindricaldriving drum (18) mounted on the lower side of the turntable (19), avertical motor drive shaft (15) rotatably mounted on said base plate (3)within the lateral confines of the outer edge of the turntable and thedrum (18), a pulley (14) on said shaft (15) in horizontal register withthe drum (18), said pulley (14) having two contiguous parallel V-grooves(16, 17) of different diameters, an elastic belt (13) of substantiallysquare cross section adapted to embrace the driving drum with a flatside of the belt and one or the other of said V-grooves with twocontiguous sides of the belt, a normally stationary shifter fork (9)embracing the belt (13) and being mounted on the base for transversemovement relative to the belt to shift the belt from one V-groove to theother, a over center snap action spring connected between the fork andthe base plate governing the stationary positions and movements of thefork, and a plunger rod (6) slidably disposed in said bearing sleeve (5)and having its upper end disposed above the plane of the recordsupporting face (21) of the turntable whereby said rod (6) can be raisedor depressed by the fingers of the operator, said plunger rod (6) beingconnected at its lower end to the fork (9) to provide said transversemovement.